Colouring of wool, silk and other protein-base fibrous materials



United. States Patent 2,987,368 COLOURING 0F WOOL, SILK AND OTHER PROTEIN-BASE FIBROUS MATERIALS Charles Bane, London, England, assignor of one-half to A. P. De Biro & Company Limited, London, England, a British company No Drawing. Filed May 6, 1958, Ser. No. 733,274 7 Claims. (Cl. 8-43) This invention relates to the colouring of wool, nylon, Acrilan, silk and the like protein-base fibrous materials, and is concerned with a method of colouring without the use of dyes.

According to the present invention there is provided in a method of colouring a protein-base fibrous material, the steps of producing a basic colour on the material comprising treating the material in a hot, aqueous, first bath containing a small proportion of sulphuric or hydrochloric acid and a small proportion of an amino-naphthol mono-, or di-sulphonic acid, or a naphthylamine mono-, or di-, or tri-sulphonic acid, and thereafter treating the material in a cold, aqueous, second bath containing a small proportion of sodium nitrite. 7

When an aminonaphthol mono-, or di-sulphonic acid, such as H-acid or 1-amino-2-naphthol-4-sulphonic acid is employed in the process outlined above a substantially permanent colour is developed by treating the material in a third bath with a coloured inorganic salt of a metal. The salt may be admixed either with ammonia or with sulphuric or hydrochloric acid, depending upon the colour it is desired to produce. The coloured inorganic salt may be a sulphate or chloride of copper, nickel or cobalt, or may be potassium bichromate. The use of ferrous sulphate will also cause a colour to be developed on the material, but ferrous sulphate is desirably not employed because it causes the fibres to break. Salts other than those exemplified either do not give fast colours, or deleteriously affect the fibres in some way. Using this method to develop the colour, the best results, i.e. fast and bright colours, are obtained with wool, although colours of varying degrees of fastness and brightness can be produced on other protein-base fibrous materials.

When, however, a naphthylamine sulphonic acid, is employed in the first bath, a substantially permanent colour is developed on the material by allowing the material to remain in the second bath until the desired permanent colour appears. Using this method to develop the colour, the best results are obtained with nylon, but again colours of varying degrees of fastness and brightness can be produced on other protein-base fibrous materials. a

The temperature of the first bath is between 50 and 100 C., but is preferably between 80 and 90 C., and the concentration of the sulphuric or hydrochloric acid is generally between 2 and l 2% by Weight of commercial concentrated acid basedon the material, The material is generallytreated in the hot bath for a period of approximately 30 minutes. H

The cold bath is generallyat a temperature of between 30 and 40 C., and preferably between 30 and 35 C. for W001, and between 35 and 40 C. for nylon, and the concentration of sodium nitriteis generally between 0.5 and 3% by weight based on the material. The material is normally left in the cold .bath for 15 to 30 minutes.

in order to show that the protein-base material takes part in the reaction performed upon the material to produce the desired colouring, tests were carried out on wool to which sulphuric acidand' sodium nitrite were first added, and the wool was given further treatment in a bath containing betanaphthol. It was found that a primary colour was first formed on the wool fibres, and that this colour could'be altered, i.e. developed into a ICC stable form, by the addition of copper sulphate and sulphuric acid. It was clear that the wool fibres had taken part in the reaction since the betanaphthol could not of course form the necessary diazo group allowing a colouring matter to be formed.

A silk sample was then subjected to the action of sulphuric acid and sodium nitrite until it took on a pronounced yellow colour. When a portion of the sample thus treated was exposed to the effect of light it was no longer possible to form a primary colour in a betanaphthol solution with that portion. This showed that exposure to light induces, as in most diazo compounds, the decomposition of the diazo groups formed on the silk.

The use of an aminonaphthol or naphthylamine sulphonic acid reduces the extent'of the chemical change taking place in the protein-base fibrous material, and smaller amounts of sulphuric acid and sodium nitrite are required than in the usual diazotization reaction. If an aminonaphthol or naphthylamine sulphonic acid is first diazotized, without the presence of the protein-base fibrous material, the same primary colour cannot be produced by any amount of subsequent treatment.

Where the first bath contains an aminonaphthol mono-, or (ii-sulphonic acid, the protein-base fibrous material is generally first soaked in hot water at a temperature of between 50 and 100 C. and the temperature is generally then lowered to between 40 and 50 C. before the addition of the acids, after which the bath is raised to a temperature of between and C. and held at this temperature for a period of approximately 30 minutes. The sulphuric or hydrochloric acid is present in a proportion of from 2 to 12% by weight based on the material, and the aminonaphthol sulphonic acid is present in a proportion of 0.5 to 8% by weight based on the material. Thus use of H-acid (l-amino-8-naphthol-3,6-disulphonic acid) is of particular importance since it allows several colours to be produced by varying the concentration of the H- acid and, by using different metallic salts for developing the final colour from the primary colour, various shades of blue, brown, black and grey may be obtained, Various shades of green may be obtained using l-amino-Z- naphthol-4-sulphonic acid, while various shades of wine may be obtained using -y-acid (2-amino-8-naphthol-6-sulphonic acid).

Where the first bath contains a naphthylamine mono-, di-, or tri-sulphonic acid, some of the first bath (about 25%) may be included in the second bath. The proportion of sodium nitrite is generally between 1 and 3% by weight based on the material, and the material is normally left in the cold bath for 15 to 30 minutes.

It should be noted that various shades of the colours may be obtained by varying the concentrations of the aminonaphthol sulphonic acid, or naphthylamine sulphonic acid, the sodium nitrite and the sulphuric or hydrochloric acid.

For a better understanding of the invention, some examples will now be given. In the following examples, all the proportions are by weight based on the proteinbase fibrous material.

EXAMPLE I Production of a deep block colour on W001 W001 is immersed'in boiling water for 20 to 30 minutes. The temperature of the Water is then dropped to 4050 C., and 2%of sulphuric acid and 5.0% of H-acid are added to the bath, the H-acid being first dissolved in hot water. The temperature is then raised to 85-90 C. and the bath is maintained at that temperature for approximately 30 minutes. The hot bath is drained ofi from the treated wool and the material is agitated until cold in cold water. 1% of sulphuric acid is first added to the cold water, and then 2.0% of sodium nitrite is added to the cold water, the wool being maintained in the nitrite bath at 30-35 C. for 30 to 35 minutes and being tested repeatedly to determine when the appropriate primary colour is obtained. The nitrite bath is then drained oif from the wool and replaced by cold water.

10% of ammonia and 6% of copper sulphate (both first separately dissolved in hot water) and thoroughly mixed are added to the new cold water bath in which the coloured wool is maintained for approximately 10 minutes. The temperature of the bath is raised to 70- 75 C., the pH value being approximately 8, and the wool is kept at this temperature for at least 20 minutes until the desired final colour is obtained on the fibres. Finally the coloured wool is rinsed twice with cold water.

It should be noted that when the cold water is added to the Wool after the hot treatment at 85-90 C., care should be taken not to lose any of the new cold Water bath since the acid washed off from the wool into solution plays an important part in producing the primary colour. It is also highly desirable that the Wool should be thoroughly cooled before the nitrite is added since imperfectly cooled material tends to be patchy after the nitrite treatment.

EXAMPLE 11 Production of a bluish-black colour on wool by means of H-acid Wool is immersed in boiling water for 20 to 30 minutes. The temperature of the water is then dropped to 40-50 C., and 4.0% of sulphuric acid and 4.0% of 100% H-acid are added to the bath, the H-acid being first dissolved in hot water. The temperature is then raised to 85-90 C. and the bath is maintained at that temperature for approximately 30 minutes. The hot bath is drained off from the treated Wool and the material is agitated until cold in cold water. 1.5 of sodium nitrite is added to the cold water, the Wool being maintained in the nitrite bath at 3035 C. for 30 to 35 minutes and being tested repeatedly to determine when the appropriate primary colour is obtained. The nitrite bath is then drained off from the wool and replaced by cold water.

8% of ammonia and 4% of copper sulphate (first separately dissolved in hot Water) are thoroughly mixed and added to the new cold water bath in which the coloured wool is maintained for approximately minutes. The temperature of the bath is raised to 70-75 C., the pH value being approximately 8, and the wool is kept at this temperature for 20 minutes until the desired final colour is obtained. Finally the coloured wool is rinsed twice with cold water.

By following the procedure of Example II, and by varying the concentration of the reagents, as outlined in the following Examples III to VII, various blue shades were produced, nickel sulphate being employed instead of copper sulphate to produce blue shades with a purple tinge.

EXAMPLE 111 Production of a medium blue colour on wool 2.0% H-acid 2.5 sulphuric acid 0.5% sodium nitrite 1.0% copper sulphate (OuSO 5.0% ammonia (NH OH) EXAMPLE IV Production of a dark blue colour on wool 3.0% H-acid 3.0% sulphuric acid 0.7% sodium nitrite 1.5% copper sulphate 5.0% ammonia EXAMPLE VI Production on wool of a navy blue colour having a purple tinge 3.0% H-acid 3.2% sulphuric acid 1.0% sodium nitrite 1.5% copper sulphate 5.0% ammonia EXAMPLE VII Production on wool of a medium blue colour having a purple tinge 2.0% H-acid 2.5% sulphuric acid 0.5% sodium nitrite 1.5% nickel sulphate 5.0% ammonia EXAMPLE VIII Production of a light brown colour on wool Wool is immersed in boiling water for 20 to 30 minutes. The temperature of the water is then dropped to 4050 C. and 1.5% of sulphuric acid and 0.5% of 100% H-acid are added to the bath, the H-acid being first dissolved in hot water. The temperature is then raised to 85-90 C. and the bath is maintained at that temperature for approximately 30 minutes. The hot bath is drained off from the treated wool, and the wool is agitated until cold in cold water. 0.7% sodium nitrite is added to the cold water, and the wool is maintained in the nitrite bath at 30-35 C. for 30 to 35 minutes, the wool being tested repeatedly to determine when the appropriate primary colour is obtained. 0.5 of sulphuric acid is added to the bath with mixing and, after 10 minutes, 0.5 of potassium bichromate (K Vr- O is added. The temperature of the bath is then gradually raised to -85 C. and maintained at this value for 20 minutes until the desired final colour is obtained. Finally the coloured wool is rinsed once with cold water.

By following the procedure of Example VIII and by varying the proportions of the reagents as outlined in the following Examples IX to XIH, various brown shades may be obtained. If it is desired to obtain a purplish brown shade, the second addition of sulphuric acid is not necessary, and the potassium bichromate may be added to the nit-rite bath when the appropriate primary colour has been obtained.

EXAMPLE IX Production of a chow brown colour on wool 1.0% H-acid 3.0% sulphuric acid 0.7% sodium nitrite 0.5% sulphuric acid 0.5% potassium bichromate EXAMPLE X Production of a medium brown colour on wool 2.0% H acid 4.0% sulphuric acid 1.0% sodium nitrite 1;0% sulphuric acid 1.0% potassium bichromate 5 EXAMPLE XI Production of a dark brown colour on wool 2.0% H-acid 4.0% sulphuric acid 1.5% sodium nitrite 1.0% sulphuric acid 1.0% potassium bichromate EXAMPLE XII Production of a medium purplish-brown colour on wool 2.0% H-acid 3.0% sulphuric acid 1.0% sodium nitrite 1.0% potassium bichromate EXAMPLE XIH Production of a dark purplish-brown colour on wool 3.0% H-acid 3.0% sulphuric acid 1.0% sodium nitrite 1.0% potassium bichromate EXAMPLE XIV Production of a green colour on wool with 1-amin0-2 napthl-4-sulphonic acid The wool is immersed in boiling water for 20-30 minutes. The temperature of the hot bath is then adjusted to 4050 C. and 3.0% of H 80 and 0.5% of l-amino-Z- naphthol-4-sulphonic acid are added to the bath. The amino acid should first be dissolved in hot water before addition to the bath. The temperature is then raised to 80-90 C. and the bath is maintained at that temperature for approximately 30 minutes.

The hot bath is drained off completely from the wool and the wool is agitated for 5 to 6 minutes in cold Water until it cools off. 0.7% of an aqueous solution of sodium nitrite is added to the bath and the wool is maintained in the nitrite bath for approximately 30 minutes; repeated samples are then taken at a few-minute intervals until the appropriate primary colour is obtained. The nitrite bath is drained 0E and the treatment container is then topped up with fresh cold water. 6.0% of ammonia and 2% of copper sulphate (both in aqueous solution) are then thoroughly mixed and added to the new bath which is maintained in the cold state for a few minutes. The temperature is raised to 7075 C., the pH value being approximately 8, and the material is treated for a period of 20 minutes until a final colour is obtained on the fibres. The material is then given one rinse.

By following the procedure of Example XIV and by varying the proportions of the reagents, as outlined in the following Examples XV to XVH, various other shades of green may be obtained.

EXAMPLE XV Production of a light green colour on wool l-amino-2-naphthol-4-sulphonic acid sulphuric acid sodium nitrite copper sulphate ammonia EXAMPLE XVI Production of a medium green colour on wool r 6 EXAMPLE XVII Production of a dark green colour on wool 3.0% 1-amino-2-naphthol-4-sulphonic acid 3.0% sulphuric acid 0.7% sodium nitrite 4.0% copper sulphate 7.0% ammonia EXAMPLE XVIII Production of a dark pink colour on nylon Nylon is treated in an aqueous bath containing 7.0% of sulphuric acid and 3.0% of l-naphthylamine-4-sulphonic acid. The bath is maintained at a temperature of 85-90 C. for a period of 30 minutes. The major part of the bath (75%) is then run ofi from the treated nylon and replaced by cold water so that the pH of the bath is between 2 and 3, and the temperature is not less than 40 C. The nylon is then agitated for 5 to 6 minutes. 2.0% of sodium nitrite in aqueous solution is then added to the cold water and the material is kept in the nitrite bath for 15 to 20 minutes until the desired final colour is achieved. The coloured material is then given a single rinse in cold water.

EXAMPLE XIX Production of a bright yellow colour on nylon The directions of Example XVIII are followed except that the hot aqueous bath contains 7.0% of sulphuric acid and 2% of 2-naphthylamine-5,7-disulphonic acid (amino J-acid).

EXAMPLE XX Production of a vivid light brown colour on nylon The directions of Example XVIII are again followed, except that the hot aqueous bath contains 7.0% of sulphuric acid and 3% of Cleves acid.

I claim:

1. A method of coloring a woollen material, which comprises soaking said material in hot water at a temperature of from 50-100 C., subjecting the resulting soaked material to the action of an aqueous first bath at a temperature of from -90 C. and containing from 2-12% by weight, based on said material, of an inorganic acid selected from the group consisting of sulphuric acid and hydrochloric acid, and from 0.58% by weight, based on said material, of an organic acid selected from the group consisting of amino-naphthol mono-sulphonic acids and amino-naphthol di-sulphonic acids, subjecting the treated material to the action of an aqueous second bath at a temperature of from 3040 C. and containing from 0.5-3% by weight, based on said material, of sodium nitrite, and thereafter developing a substantially permanent color on the resulting treated material by heating said material in a third bath at a temperature below C. and containing a color inorganic salt selected from the group consisting of the chlorides of copper, nickel and cobalt, the sulphates of copper, nickel and cobalt, and potassium bichromate, until the desired color appears.

2. A method as claimed in claim 1, wherein said colored inorganic salt is added to said second bath to form said third bath.

3. A method of coloring a woollen material, which comprises soaking said material in hot water at a temperature of from 50-100" C., lowering the temperature of the water to between 40 and 50 C., adding from 2-12% by weight, based on said material, of an inorganic acid selected from the group consisting of sulphuric acid and hydrochloric acid, and from 0.58% by weight, based on said material, of an organic acid selected from the group consisting of amino-naphthol mono-sulphonic acids and amino-naphthol di-sulphonic acids, raising the temperature of the resulting aqueous *7 first treating bath to from 85-90 C. for a period of about 30 minutes, subjecting thetreated material to the action of an aqueous second bath at a temperature of from 30-40 C. and containing from 0.5-3% by weight,

based on said material, of sodium nitrite, replacing the aqueous sodium nitrite treating bath 'by'cold Water to which a colored inorganic salt selected from the group consisting of the chlorides of copper, nickel and cobalt, the sulphates of copper, nickel and cobalt, and potassium bichromate, is added to'forma third treatment bath, and thereafter heating said third bath to a temperature below 85 C. until the desired color appears.

4.-A method as claimed in claim 3, wherein said colored inorganic salt is admixed with an inorganic acid selected'from the group consisting of sulphuric acid and hydrochloric acid.

5. A method as claimed in claim 3, wherein said colored inorganic salt of a metal is admixed with suificient ammonia to maintain the pH of the third treatment bath at a value of about 8.

6. A method as claimed in claim 3, wherein the aminonaphthol sulphonic acid is selected from the group consisting of I-I-acid, 1-amino-2-naphthol-4-sulphonic acid and 'y-acid.

7. A method of coloring a woollen material, which comprises subjecting the material to the action of a hot,

aqueous first bath containing from 212% by weight, based on said material,'of an inorganic acid selected from the group consisting of sulphuric acid and hydrochloric acid, and from O.58% by weight, based on said material, of an organic acid selected from the group consisting of amino-naphthol mono-sulphonic acidsand amino-naphthol di-sulphonic acids, subjecting the treated material to the action of a cold, aqueous second bath containing from (LS-3% by weight, based on said material, of sodium nitrite, and thereafter developing a substantially permanent color on the woollen material by heating said material in a third bath containing a colored inorganic salt selected from the group consisting of the chlorides of nickel, copper and cobalt, the sulphates of nickel, copper and cobalt, and potassium bichromate, at'a temperature below 85 C. until the desired color appears.

References Cited in the file of this patent UNITED STATES PATENTS 1,231,492 Chester June 26, 1917 1,864,718 Feibelmann June 28, 1932 1,926,556 Nuesslein Sept. 12, 1933 2,209,251 Rein July 23, 1940 2,284,387 Gordon May 26, 1942 2,321,816 Huss June 15, 1943 

7. A METHOD OF COOLING A WOOLLEN MATERIAL, WHICH COMPRISES SUBJECTING THE MATERIAL TO THE ACTION OF A HOT, AQUEOUS FIRST BATH CONTAINING FROM 2-12% BY WEIGHT, BASED ON SAID MATERIAL, OF AN INORGANIC ACID SELECTED FROM THE GROUP CONSISTING OF SULPHURIC ACID AND HYDROCHLORIC ACID, AND FROM 0.5-8% BY WEIGHT, BASED ON SAID MATERIAL, OF AN ORGANIC ACID SELECTED FROM THE GROUP CONSISTING OF AMINO-NAPHTHOL MONO-SULPHONIC ACIDS AND AMINO-NAPHTHOL DI-SULPHONIC ACIDS, SUBJECTING THE TREATED MATERIAL TO THE ACTION OF A COLD, AQUEOUS SECOND BATH CONTAINING FROM 0.5-3% BY WEIGHT, BASED ON SAID MATERIAL, OF SODIUM NITRITE, AND THEREAFTER DEVELOPING A SUBSTANTIALLY PERMANENT COLOR ON THE WOOLLEN MATERIAL BY HEATING SAID MATERIAL IN A THIRD BATH CONTAINING A COLORED INORGANIC SALT SELECTED FROM THE GROUP CONSISTING OF THE CHLORIDES OF NICKEL, COPPER AND COBALT, THE SULPHATES OF NICKEL, COPPER AND COBALT, AND POTASSIUM BICHROMATE, AT A TEMPERATURE BELOW 85*C. UNTIL THE DESIRED COLOR APPEARS. 